English literature of the 17th—18th centuries. Enlightenment

Frederick the Great in Prussia being merely an early and outstanding example.
The passion of the Enlightenment for the improvement and reform of society makes it an important element of the climate of opinion which prevails in the early stages of the French Revolution (and survives today in the ideals of the social services of democratic nations).
But such principles contain their own flaws. The Enlightenment's optimism can be a recipe for disappointment and is easily mocked (as by Voltaire himself in Candide). And too much reason is dry fare. People crave something more emotionally nourishing. This is provided in religious terms by the 18th-century revivalists. And the need to listen to the emotions is forcefully expressed by a child of the French Enlightenment, Jean-Jacques Rousseau.